(Summary based on an article by Valerie G.A. Grossman, RN, CEN, CCRN, originally published in Journal of Emergency Nursing, August 1997, pages 367-373.)

Paroxysmal supraventricular tachycardia (PSVT) is the most frequently occurring tachyarrhythmia in children. Diagnosed in 1 of every 250-1000 children, PSVT may occur at various timepoints in a child's life cycle, including in utero. Within 10 months of birth PSVT will be outgrown by 93% of the infants diagnosed with it; however, 35% of these children will have a recurrence of PSVT in early childhood, most likely between the ages of 5 and 8 years.

Broadly defined, PSVT refers to the sudden onset and spontaneous relief of any rapid, regular dysrhythmia that shows no visible P waves (thereby making a more specific identification impossible). While cases of PSVT possess similar EKG features, the physiologic mechanism varies. In general, premature atrial or ventricular contraction, sinus node acceleration, or sinus pauses with a junctional escape beat are common precursors to PSVT; however, at least 16 different types of pediatric PSVT have been identified. Of these, most can be linked to either increased automaticity or reentry within the cardiac conduction system.

Fortunately, signs and symptoms of PSVT have been identified and can be used as a guide when diagnosing and selecting treatment. In infants and children a heart rate >220 or >150-250 beats per minute, respectively, combined with a sudden onset and abrupt termination of rhythm, a QRS less than 0.08-0.12 seconds, a regular rhythm with no beat-to-beat variability, and a rate-related ST depression of 1 to 8 mm, are reliable indicators. Additionally, parents of infants may report pallor, poor feeding, restlessness, irritability and/or vomiting, while older children may report chest pain, dizziness, pallor, shortness of breath and/or palpitations.

Although many children with a history of PSVT can be taught to convert their own episodes independently via vagal maneuvers (retching, vomiting, coughing, breath holding, etc.), "...immediate transfer to an emergency department should be made for all pediatric patients who have no prior history of PSVT, have a known history of PSVT and are symptomatic, or are in hemodynamically unstable condition."

According to this author, "The treatment of choice for symptomatic patients without cardiac compromise is IV administration of adenosine." In addition to strong efficacy, adenosine has limited side effects and a half-life of only 5 to 10 seconds. The author also noted that while intravenous infusions of propranolol and verapamil are sometimes used for PSVT in adults, these drugs are contraindicated in young pediatric patients and may result in "...long-duration adrenergic and calcium channel blockade causing cardiovascular collapse, profound bradycardia, and death in the younger child."

Other options for long-term medical treatment of pediatric PSVT include digoxin (except in children with Wolff-Parkinson-White syndrome) or, if digoxin fails, oral propranolol. Calcium channel blockers are often ineffective.

While seldom life-threatening, pediatric PSVT calls for the education of not only medical providers, but also children, parents and other family members regarding PSVT symptoms and treatment. Home management techniques should be taught to the child and other family members and, when necessary, appropriate medical treatment should immediately be administered.